Coastal engineering

An integrated coastal ocean and acoustic propagation model has been implemented to determine the effects of the ocean variations on the acoustic propagation field applied specifically to SFOMC. The ocean dynamics were modeled using the sigma coordinate, orthogonal curvilinear grid, Princeton Ocean Model. By using forcing conditions of tide, river runoff, wind and realistic bottom topography, the resulting time variant regional sound velocity outputs from the model were used as inputs to the range dependent, parabolic equation, acoustic propagation model, RAM. The results show that the fluctuations in the ocean result in scintillation in the acoustic propagation field, and for higher frequencies this variability is uniformly distributed and at times as much as +/-3 dB. High resolution in the POM grid and the range and depth sizes for RAM were important for obtaining reliable simulation results.